Field of the Invention
The present invention relates generally to an apparatus for performing electrical discharge machining operations on workpieces.
Description of the Prior Art
Electrical discharge machining (EDM) is a well-known process for machining electrical parts, particularly when high precision is required. In such previously known machines, the workpiece to be machined is positioned within a working tank which is at least partially filled with a dielectric liquid.
In order to perform the machining operation, an EDM probe or electrode is brought into contact with the workpiece which, through electrical discharge from the probe to the workpiece, ablates material from the workpiece thus performing the desired machining operation.
Since at least a portion of the workpiece is submerged within the dielectric fluid during the machining operation, an upper edge or rim of the holding tank must necessarily be positioned near or above the top of the workpiece. As such, the holding tank interferes with the removal of the finished workpiece from the workpiece holding means in the holding tank as well as the attachment of a new workpiece to the workpiece to be machined in the holding tank.
While the interference of the holding tank poses a relatively minor inconvenience when the workpieces are manually removed from and secured to the workpiece holder, the interference presented by the holding tank poses a more serious problem when the workpieces are secured to and removed from the workpiece holder by automatic material handlers or robots. In such situations, it is often times necessary for the automatic material handlers to include additional axes of movement in order to manipulate the workpiece through the top of the holding tank. Because of this, it has not been practical to automate many EDM operations.